After installing Gentoo on MacOS I was first able to emerge some packages.
At some point I started getting error messages during the ./configure run:

Quote:

macos
configure: WARNING: If you wanted to set the --build type, don't use --host.
If a cross compiler is detected then cross compile mode will be used.
checking for a BSD-compatible install... /bin/install -c
checking whether build environment is sane... yes
checking for gawk... no
checking for mawk... no
checking for nawk... no
checking for awk... awk
checking whether make sets $(MAKE)... yes
checking for powerpc-apple-darwin-strip... no
checking for strip... strip
checking build system type... configure: error: /bin/sh config/config.sub -apple-darwin7.4.0 failed

I now have the same problem with my hand-compiled CVS Emacs. The only difference:

You've probably installed the gnu version of coreutils and installed the gnu version of uname. You'll need to get a copy of the original. A new version of coreutils has been written to address this problem.